The sophistication of devices developed by terrorists has left airports struggling to keep up with the technology needed to detect them, security experts admitted yesterday.

Tougher measures worldwide were demanded yesterday by the US Transportation Security Administration as it sought to prevent a repeat of the lapses that allowed a bomber on to flight 253 on Christmas Day.

New measures immediately put in place at Heathrow and other British airports included stricter security checks such as more frequent body searches just prior to boarding, and a strict limit of one item of hand luggage. Some airlines will now compel passengers to sit in their seats for the last hour of a flight.

The Secretary of State for Transport, Lord Adonis, said last night: "Passenger safety is my paramount concern. We are co-operating closely with the US on additional security controls at airports. These measures have now been put in place. There are currently some delays to transatlantic flights, so passengers should contact their airline before travelling."

Until a decade ago the metal detectors and X-ray machines used in airports were a reasonable safeguard against bombs being smuggled on board aircraft, but today they amount to little more than a deterrent. The explosive devices developed by terrorist networks has made metal timers, batteries and detonators redundant and leaves security staff having to find new ways of detecting suspect substances.

The answer, security advisers believe, is for airport security personnel to rely less on technology to pinpoint a terrorist and more on their own skills at spotting unusual patterns of behaviour among passengers.

Explosives detectors do exist but airports are reluctant to use them because they are slow and cause passengers to take four times as long to get through security. Sensors designed to detect suspect liquids were supposed to be in place next year in Europe but have now been postponed to 2013 by the EU. Other detectors, such as the machine that can see underneath clothing without passengers having to undress, are being tried out.

Chris Yates, an independent expert with Yates Consulting, said the machinery will play a part in spotting potential terrorists but only in conjunction with human skills. He doubts whether any security system can be perfect, regardless of how efficient it is. "Although we make our procedures as secure as we can, they are never 100 per cent sure," he said. "You can array all the technology in the world but ultimately somebody will find some way round. We are in a state of permanent catch-up."

Since the 9/11 attacks, US airports have introduced increasingly restrictive rules on what passengers can take on board aircraft. In the immediate aftermath the emphasis in Britain and the US was on preventing any item with the potential of being used as a weapon being taken on board. Razors, nail scissors, tweezers and umbrellas all fell foul of the new rules.

When Richard Reid, the shoe bomber, attempted to blow up a flight from Paris to Miami in December 2001, passengers were ordered to take off their shoes to be screened with their hand luggage by the X-ray machines. Further restrictions were brought in less than five years later when a plot to destroy at least seven aircraft using liquid bombs was uncovered. Passengers were briefly barred from carrying any liquids on to the aircraft.

Philip Baum, editor of Aviation Security International and managing director of the Greenlight consultancy, believes it is essential to introduce routine passenger profiling in which security staff use background information and assess the behaviour of individuals to pick out potential terrorists. It has already been used successfully in Israel and elements of it have been taken up in Britain and the US.

"We ought to differentiate between passenger types on their appearance and behaviour. And when I say appearance I don't mean race, creed or colour. I mean their facial expressions, their movement, the degree of stress they are under, how they interact with the people they are with, and how well they fit in with the type of passenger normally found on that route."

The technique was used by the Israelis in 1986 when a pregnant Irish woman was identified as a potential threat. She was found to have been unwittingly carrying a bomb placed in her bag by her lover. It is one of the reasons why passengers are now asked if they have packed their own bags.

If the attempt to obliterate Northwest Airlines flight 253 came as a shock for the United States in the middle of its Christmas holiday, the suggestion that the would-be bomber came from West Africa via al-Qa'ida should not have been a complete surprise.

More than eight years after the 11 September attacks, the United States is still aware of the significance of al-Qa'ida, but the group has appeared less of a clear and present danger as the years have passed. However, less than a week before the Nigerian student Abdul Farouk Abdulmutallab boarded his flight to Detroit, The Washington Post had warned, grimly and prominently, of a new source of concern from the terror group.

An article warning of "worrying signs" that al-Qa'ida sympathisers were bringing "a violent brand of Islam to moderate parts of West Africa" catalogued a series of attacks in recent months that have accentuated fears that a group, mainly of Algerians, were threatening to radicalise areas where Muslims were in the majority. Al-Qa'ida in the Islamic Maghreb (Aqim) was held responsible for the execution of the Briton Edwin Dyer and an army colonel in Mali, the killing of an American teacher and a suicide bombing in Mauritania, as well as the kidnapping of two Canadian diplomats in Niger. The recent arrest of three Malian al-Qa'ida suspects in Ghana, over claims that they were conspiring to smuggle South American cocaine through Africa, can be added to evidence that terrorists are taking advantage of disease, poverty, a disenchantment with authority and breakdown of the rule of law in large areas. While Western intelligence services have focused on the growing terrorist threat from East Africa, some of the most dangerous groups have been prospering on the other side of the continent.

Mali has become the centre of al-Qa'ida activity since the group arrived from the north in 2007. The extremist Algerians who made up the Salafist Group for Preaching and Jihad settled in the Malian desert and quickly renamed themselves Aqim. The West African wing of al-Qa'ida has been accused of gun-running, kidnapping, murder and now, for the first time, involvement in the drugs trade.

Intelligence analysts also maintain that Aqim has been seeking new recruits in large, "ungovernable" swathes of nation-states – many of which have large Muslim populations – mimicking al-Qa'ida in Pakistan and Afghanistan.

Encouraged by CIA warnings over the growing threat posed by the region, the US has diverted some $500m (£313m) to bolster the counter-terrorism capabilities of 10 countries – although some critics have complained that the effort has not produced lasting results so far.

The near-miss experienced over Detroit last week offered a chilling reminder that al-Qa'ida has not gone away but, in fact, has spread its tentacles far beyond its original base. The Americans and their allies in West African governments will be under intense pressure to turn the tide and prove that they are winning the battle.